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.\" Copyright (c) 2009 Sun Microsystems, Inc. All Rights Reserved.
.\" Copyright 2011 Joshua M. Clulow <josh@sysmgr.org>
.\" Copyright (c) 2011, 2019 by Delphix. All rights reserved.
.\" Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
.\" Copyright (c) 2014, Joyent, Inc. All rights reserved.
.\" Copyright (c) 2014 by Adam Stevko. All rights reserved.
.\" Copyright (c) 2014 Integros [integros.com]
.\" Copyright 2019 Richard Laager. All rights reserved.
.\" Copyright 2018 Nexenta Systems, Inc.
.\" Copyright 2019 Joyent, Inc.
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.Dd July 11, 2022
.Dt ZFS-SNAPSHOT 8
.Os
.
.Sh NAME
.Nm zfs-snapshot
.Nd create snapshots of ZFS datasets
.Sh SYNOPSIS
.Nm zfs
.Cm snapshot
.Op Fl r
.Oo Fl o Ar property Ns = Ns Ar value Oc Ns …
.Ar dataset Ns @ Ns Ar snapname Ns …
.
.Sh DESCRIPTION
Creates a snapshot of a dataset or multiple snapshots of different
datasets.
.Pp
Snapshots are created atomically.
That is, a snapshot is a consistent image of a dataset at a specific
point in time; it includes all modifications to the dataset made by
system calls that have successfully completed before that point in time.
Recursive snapshots created through the
.Fl r
option are all created at the same time.
.Pp
.Nm zfs Cm snap
can be used as an alias for
.Nm zfs Cm snapshot .
.Pp
See the
.Sx Snapshots
section of
.Xr zfsconcepts 7
for details.
.Bl -tag -width "-o"
.It Fl o Ar property Ns = Ns Ar value
Set the specified property; see
.Nm zfs Cm create
for details.
.It Fl r
Recursively create snapshots of all descendent datasets
.El
.
.Sh EXAMPLES
.\" These are, respectively, examples 2, 3, 10, 15 from zfs.8
.\" Make sure to update them bidirectionally
.Ss Example 1 : No Creating a ZFS Snapshot
The following command creates a snapshot named
.Ar yesterday .
This snapshot is mounted on demand in the
.Pa .zfs/snapshot
directory at the root of the
.Ar pool/home/bob
file system.
.Dl # Nm zfs Cm snapshot Ar pool/home/bob Ns @ Ns Ar yesterday
.
.Ss Example 2 : No Creating and Destroying Multiple Snapshots
The following command creates snapshots named
.Ar yesterday No of Ar pool/home
and all of its descendent file systems.
Each snapshot is mounted on demand in the
.Pa .zfs/snapshot
directory at the root of its file system.
The second command destroys the newly created snapshots.
.Dl # Nm zfs Cm snapshot Fl r Ar pool/home Ns @ Ns Ar yesterday
.Dl # Nm zfs Cm destroy Fl r Ar pool/home Ns @ Ns Ar yesterday
.
.Ss Example 3 : No Promoting a ZFS Clone
The following commands illustrate how to test out changes to a file system, and
then replace the original file system with the changed one, using clones, clone
promotion, and renaming:
.Bd -literal -compact -offset Ds
.No # Nm zfs Cm create Ar pool/project/production
  populate /pool/project/production with data
.No # Nm zfs Cm snapshot Ar pool/project/production Ns @ Ns Ar today
.No # Nm zfs Cm clone Ar pool/project/production@today pool/project/beta
  make changes to /pool/project/beta and test them
.No # Nm zfs Cm promote Ar pool/project/beta
.No # Nm zfs Cm rename Ar pool/project/production pool/project/legacy
.No # Nm zfs Cm rename Ar pool/project/beta pool/project/production
  once the legacy version is no longer needed, it can be destroyed
.No # Nm zfs Cm destroy Ar pool/project/legacy
.Ed
.
.Ss Example 4 : No Performing a Rolling Snapshot
The following example shows how to maintain a history of snapshots with a
consistent naming scheme.
To keep a week's worth of snapshots, the user destroys the oldest snapshot,
renames the remaining snapshots, and then creates a new snapshot, as follows:
.Bd -literal -compact -offset Ds
.No # Nm zfs Cm destroy Fl r Ar pool/users@7daysago
.No # Nm zfs Cm rename Fl r Ar pool/users@6daysago No @ Ns Ar 7daysago
.No # Nm zfs Cm rename Fl r Ar pool/users@5daysago No @ Ns Ar 6daysago
.No # Nm zfs Cm rename Fl r Ar pool/users@4daysago No @ Ns Ar 5daysago
.No # Nm zfs Cm rename Fl r Ar pool/users@3daysago No @ Ns Ar 4daysago
.No # Nm zfs Cm rename Fl r Ar pool/users@2daysago No @ Ns Ar 3daysago
.No # Nm zfs Cm rename Fl r Ar pool/users@yesterday No @ Ns Ar 2daysago
.No # Nm zfs Cm rename Fl r Ar pool/users@today No @ Ns Ar yesterday
.No # Nm zfs Cm snapshot Fl r Ar pool/users Ns @ Ns Ar today
.Ed
.
.Sh SEE ALSO
.Xr zfs-bookmark 8 ,
.Xr zfs-clone 8 ,
.Xr zfs-destroy 8 ,
.Xr zfs-diff 8 ,
.Xr zfs-hold 8 ,
.Xr zfs-rename 8 ,
.Xr zfs-rollback 8 ,
.Xr zfs-send 8
